Method and wireless device for monitoring control channel

Abstract

A method and a wireless device for monitoring a control channel in a wireless communication system are discussed. The method according to an embodiment includes receiving, from a base station, a radio resource control (RRC) signal, the RRC signal including first information on at least one subframe on which at least one enhanced physical downlink control channel (EPDCCH) is monitored; determining whether to monitor both of a physical downlink control channel (PDCCH) and the EPDCCH or only the EPDCCH on the at least one subframe indicated by the first information; and monitoring the PDCCH in a common search space of the at least one subframe and the EPDCCH in a user equipment (UE)-specific search space on the at least one subframe, if both of the PDCCH and the EPDCCH are monitored.

What is claimed is: 
     
         1 . A method of monitoring a control channel in a wireless communication system, the method comprising:
 receiving, by a wireless device, from a base station, a radio resource control (RRC) signal, the RRC signal including first information on at least one subframe on which at least one enhanced physical downlink control channel (EPDCCH) is monitored;   determining whether to monitor both of a physical downlink control channel (PDCCH) and the EPDCCH or only the EPDCCH on the at least one subframe indicated by the first information; and   monitoring, by the wireless device, the PDCCH in a common search space of the at least one subframe and the EPDCCH in a user equipment (UE)-specific search space on the at least one subframe, if both of the PDCCH and the EPDCCH are monitored.   
     
     
         2 . The method of  claim 1 , wherein the RRC signal further includes second information regarding the UE-specific search space. 
     
     
         3 . The method of  claim 1 , wherein the EPDCCH is demodulated by a demodulation reference signal (DMRS) 
     
     
         4 . The method of  claim 3 , wherein the EPDCCH in the UE-specific search space is demodulated by the DMRS which is generated based on an identifier specific to the wireless device, and
 the PDCCH in the common search space is decoded by a cell-specific reference signal (CRS) which is generated based on an identifier shared by one or more wireless devices.   
     
     
         5 . The method of  claim 1 , wherein the at least one subframe includes a plurality of orthogonal frequency division multiplexing (OFDM) symbols. 
     
     
         6 . The method of  claim 5 , wherein the common search space is started from a first OFDM symbol of the plurality of OFDM symbols, and the UE-specific search space is started from an OFDM symbol indicated by the serving cell. 
     
     
         7 . A wireless device for monitoring a control channel in a wireless communication system, the wireless device comprising:
 a radio frequency (RF) unit configured to transmit and receive a radio signal; and   a processor operatively coupled to the RF unit and configured to:
 receive, from a base station, a radio resource control (RRC) signal, the RRC signal including first information on at least one subframe on which at least one enhanced physical downlink control channel (EPDCCH) is monitored, 
 determine whether to monitor both of a physical downlink control channel (PDCCH) and the EPDCCH or only the EPDCCH on the at least one subframe indicated by the first information, and 
 monitor the PDCCH in a common search space of the at least one subframe and the EPDCCH in a user equipment (UE)-specific search space on the at least one subframe, if both of the PDCCH and the EPDCCH are monitored. 
   
     
     
         8 . The wireless device of  claim 7 , wherein the RRC signal further includes second information regarding the UE-specific search space. 
     
     
         9 . The wireless device of  claim 7 , wherein the EPDCCH is demodulated by a demodulation reference signal (DMRS) 
     
     
         10 . The wireless device of  claim 9 , wherein the EPDCCH in the UE-specific search space is demodulated by the DMRS which is generated based on an identifier specific to the wireless device, and
 the PDCCH in the common search space is decoded by a cell-specific reference signal (CRS) which is generated based on an identifier shared by one or more wireless devices.   
     
     
         11 . The wireless device of  claim 7 , wherein the at least one subframe includes a plurality of orthogonal frequency division multiplexing (OFDM) symbols. 
     
     
         12 . The wireless device of  claim 11 , wherein the common search space is started from a first OFDM symbol of the plurality of OFDM symbols, and the UE-specific search space is started from an OFDM symbol indicated by the serving cell.